1. Field of the Invention
This invention relates to a forced cooled electric motor and more particularly to a forced cooled electric motor which is equipped with ducts for applying jets of a cooling medium therethrough directly onto the surface of contact between the brush and the commutator at the commutator section of the motor whereby the motor, even though it may be small in size and weight, can furnish a very high power.
2. Description of the Prior Art
Recently, electric motors of small size and small weight and yet capable of providing a high power have been needed for battery driven automobiles, motor-boats, battery-driven radio-controlled big model airplanes, etc. For example, a magnet motor with a load current of 10A or more is desired. It has been a problem, however, how to cool the motor. A relatively simple means for a forced cooling of a motor has been the provision of a fan on the shaft of the motor. In such prior art means the flow of cooling medium caused by the fan is introduced into the interior of the motor coaxially of the motor shaft and therefore subjected to turbulence because of the existance of the shaft bearings, brush holders, etc. Thus with the prior art means it is difficult to supply a powerful flow of cooling medium onto the commutator region where commutation of big current is taking place.